Crystalline polymers, e.g. polyolefin polymers such as polyethylene, polypropylene and polybutene-1, and polyester polymers such as polyethylene terephthalate, and polyamide polymers have a slow rate of crystallization after heat forming. Consequently, the molding cycle when they are processed is too long, and as crystallization proceeds even after molding was complete, the molded product sometimes deformed. In addition, there was the disadvantage that these crystalline polymer compound materials formed large spherocrystals, so their mechanical strength and transparency was poor.
These disadvantages are due to the crystalline properties of the crystalline polymer compounds, and are known to be overcome by forming fine crystals very rapidly. Now, to produce fine crystals very rapidly, the crystallization temperature may be increased, or crystal nucleating agents and crystallization promoters may be added.
As the nucleating agent or crystallization promoter, metal salts of cyclic phosphates such as 2,2′-methylene bis(4,6-ditert-butylphenyl)phosphate are used. Japanese Patent Application Laid-Open H5-43746 and Japanese Patent Application Laid-Open 2002-338820 disclose that good results are obtained by the concurrent use of these metal salts of cyclic phosphoric acid esters and metal salts of organic fatty acids. However, there are problems because the prior art crystal nucleating agent compositions had poor miscibility with and/or dispersibility in the crystalline polymers, so they did not impart sufficient transparency when they were used.